Structure-Energy Relationships of Lithium Enolate Aggregates

这项有机和大分子化学基金为杜克大学爱德华·阿内特博士的研究提供了支持。研究了表征有机阴离子在溶液中聚集和反应性的结构-能量关系。理解这种关系对于完整地构建溶液中反应物和溶剂之间的相互作用是必不可少的。以下过程将被研究：(1)一些基本过程的能量，如锂离子与中性配体（如醚、酯、酮、醛和胺）以及与烯酸盐、酚酸盐和醇氧离子的相互作用热；(2)与烯醇酸锂的重要反应如醛缩、迈克尔缩合直接相关的反应热；(3)通过降低凝固点测定不同极性溶剂（环己烷、苯、二恶烷、二甲氧基砜和亚砜）中选定烯醇酸离子的聚集度（这些结果将与x射线晶体结构、异核磁共振、络合热有关，在有利的情况下，还与烷基化或醛醇反应的动力学分析有关）；(4)碳阳离子、碳离子和自由基的平衡，其中单电子转移的热力学和动力学可以直接与配位（两个电子转移）进行比较。

This grant in Organic and Macromolecular Chemistry provides support for the research of Dr. Edward Arnett, Duke University. The work is focused on the structure-energy relationships which characterize the aggregation and reactivity of organic anions in solution. Understanding such relationships is essential for a complete construction of the interactions between reactants and solvents in solution. The following processes will be studied: (1) the energies for a number of fundamental processes such as heats of interaction of lithium cation with neutral ligands such as ethers, esters, ketones, aldehydes, and amines and with enolate, phenolate and alkoxide ions; (2) heats of reaction of direct relevance to the important reactions of lithium enolates such as the aldol and Michael condensations; (3) the degrees of aggregation for selected enolate ions in a spectrum of solvents of varied polarity --cyclohexane, benzene, dioxane, DMSO and sulfolane-- by freezing point depression (such results will be related to x-ray crystal structures, heteronuclear NMR, heats of complexing and, in favorable cases, to kinetic analysis of alkylation or aldol reactions); (4) equilibration of carbocations, carbanions, and radicals where thermodynamics and kinetics for single electron transfer may be compared directly with coordination (two electron transfer).